Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
Fullerton's coldest month, December, generally records average temperatures ranging from a high of 64°F (17.8°C) to a low of 50.9°F (10.5°C).Humidity
The average relative humidity in December is 55%.Rainfall
The month with the most rainfall is December, when the rain falls for 6.6 days and typically aggregates up to 1.54" (39mm) of precipitation.Daylight
December has the shortest days of the year, with an average of 9h and 54min of daylight.On the first day of December, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:53 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 6.7h of sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: In December, the maximum UV index of 4 transforms into these recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What time of the year is the coldest in Fullerton?
What are the temperatures in December?
What is the average humidity in December?
What is the wettest month?
How many days does it rain in December?
What is the month with the shortest days in Fullerton?
What is the average length of the day in December?
What time are sunrise and sunset in December?
What is the month with the least sunshine?
How long on average sun shines in December?
When is the lowest UV index in Fullerton?
What is the UV index intensity in December?
Average temperature in December
Fullerton, CA
- Average high temperature in December: 64°F
The warmest month (with the highest average high temperature) is August (83.5°F).
The month with the lowest average high temperature is December (64°F).
- Average low temperature in December: 50.9°F
The month with the highest average low temperature is August (65.5°F).
The coldest month (with the lowest average low temperature) is February (50.2°F).
Average pressure in December
Fullerton, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in December
Fullerton, CA
- Average wind speed in December: 5.1mph
The windiest month (with the highest average wind speed) is April (6mph).
The calmest months (with the lowest average wind speed) are September and October (4.7mph).
Average humidity in December
Fullerton, CA
- Average humidity in December: 55%
The month with the highest relative humidity is June (65%).
The month with the lowest relative humidity is November (51%).
Average rainfall in December
Fullerton, CA
- Average rainfall in December: 1.54"
The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Fullerton, CA
- Average rainfall days in December: 6.6 days
The month with the highest number of rainy days is March (7.3 days).
The month with the least rainy days is June (1.5 days).
Average daylight in December /
Average sunshine in December
Fullerton, CA
- Average daylight in December: 9h and 5min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in December: 6h and 4min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).
Average sunshine days in December
Fullerton, CA
- Average sunshine days in December: 23.2 days
The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is February (20.6 days).
Average UV index in December
Fullerton, CA
- Average UV index in December: 4
The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 4).
Average cloud cover in December
Fullerton, CA
- Average cloud cover in December: 22
The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Fullerton, CA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Fullerton, California, USA
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